Estrone

It is a weaker estrogen, commonly found in higher quantities in postmenopausal women.

Estrone is one of the three main circulating estrogens in humans. Like estradiol, estrone is secreted by the ovaries, but it is also predominantly produced in peripheral tissues by the action of aromatase on its precursor androstenedione. Its estrogenic activity is intermediate to that of estriol, the weakest estrogen, and estradiol, the strongest. Estrone is converted to the more potent estradiol in tissues by the action of 17β-hydroxysteroid dehydrogenase, and through this conversion it represents the main source of circulating estradiol in postmenopausal women and in men.

Estrone is the predominant circulating estrogen in postmenopausal women, compared to estradiol which predominates in premenopausal women. This is because ovarian estradiol production declines significantly post-menopause while estrone production from androstenedione changes minimally compared to premenopause. The aromatization of androstenedione to estrone increases with increased body weight, since aromatase is prevalent in fat tissue. This increased availability of estrone contributes to the rise in circulating estradiol with increasing body mass index in obese postmenopausal women.

Produced by the ovaries, the estrone hormone is one of three types of estrogen, and it is one of the major hormones found in the bodies of postmenopausal women. While research into estrone function is still ongoing, largely due to the fact that it is the least powerful of the three types of estrogen, women should still understand this hormone and its known effects on the body.

Specifically, estrone (also called oestrone) is estrogen-like estradiol and estriol. Unlike the other two, estrone comes from the ovaries, as well as the adipose tissue and adrenal glands.

How Does Estrone Function?
As an estrogen, estrone is responsible for female sexual development and function. Because it is less powerful than the other estrogens, estrone can sometimes serve as a repository for estrogens, and the body can convert it to estrogen when needed.

Possible Problems with Estrone
The effects of low Estrone or high Estrone levels are not yet well known. Women who have breast cancer or men who are being treated to reduce testosterone levels — such as in prostate cancer treatment — may need to have their estrone levels monitored because estrone levels can increase in these cases. Women who are obese will produce more estrone from fatty tissue. Too much estrone has been linked to breast and endometrial cancer growth. Besides this potential outcome, other results of increased estrone levels are not yet known.

Women who have too little estrogen hormones, including oestrone, may develop osteoporosis. Low estrogen levels can also cause the symptoms of menopause, including hot flashes, fatigue, poor sex drive, and depression. For women who are postmenopausal and who are still struggling with these symptoms, low oestrone levels may be the reason. However, research has not yet found a definite link between the ovary hormone and these symptoms.

Estrone (E1), estradiol (E2), and estriol (E3) are three endogenously produced estrogens.

- Made via aromatization in several tissues like fat and muscle

- Weaker compared to Estradiol (Research says the estrogenic activity is about 4% of estradiol’s activity)

- Most abundant in menopause

- Converts into estradiol (E2)

What does Estrogen do?

1. Growth and development of female secondary sex characteristics

2. Thickens the uterus for implantation, increases vaginal acidity to protect against infection, important for vaginal lubrication (particularly E3)

3. Necessary for bone health

4. In the brain helps maintain body temperature, protects against memory loss, increases serotonin and serotonin receptors

5. Important for collagen production, skin thickness, and getting blood supply to the skin

6. Helps protect against atherosclerosis

7. Estrogen through the ER helps induce or upregulate the expression of the PR